anti-PD1 Therapy Research Articles

Final analysis of the BIMES trial, a phase II single arm study assessing efficacy and safety of bintrafusp alfa in previously treated advanced malignant pleural mesothelioma (GECP 20/09).

8084 Background: Transforming growth factor β (TGF-β) is involved in tumor immune evasion and epithelial–mesenchymal transition (EMT). As TGF-β upregulation and EMT are associated with resistance to anti-PD1 therapy, we evaluated the efficacy of bintrafusp alfa, a bifunctional fusion protein targeting TGF-β and PD-L1, in malignant pleural mesothelioma (MPM). Methods: Patients with advanced MPM who were previously treated with platinum-based chemotherapy were enrolled and received bintrafusp alfa 1200mg/m2 every 2 weeks until progression or for a maximum of two years. The primary objective was to determine the progression-free survival (PFS) by modified RECIST v1.1. assessed by the investigators. The expected median PFS was 4.5 months. Secondary objectives were overall response rate, duration of response, overall survival (OS) and safety. Results: Between October 2021 to March 2023, 47 patients were enrolled. Mean age was 70 years (41-84) and 36 (78.3%) were males. Most patients had epithelioid histology (82.9%) and had received only 1 prior line of therapy (84.8%). With a median follow-up of 11.5 months, 43 patients had disease progression and 24 patients died. The median number of doses administered was 4 (1-21) and reasons for treatment discontinuation were disease progression (82.6%), toxicity (6.5%), investigator decision (4.4%) and death (6.5%) by tumor progression. The median PFS was 1.9 months (95% CI 1.7 – 5.4) and the 6 month-PFS rate was 15.9%. Disease control rate was 34.8% (95% CI 22.2-49.9) consisting of 2 patients with partial response and 13 patients with stable disease as best response. The median OS was 11.9 months (95% CI 4.4 – not reached) and 6, 12 and 18-month OS rate was 65.3%, 46.5% and 26.6%, respectively. No significant differences in OS and PFS were observed based on MPM histological subtype. Grade 3-4 treatment-related adverse events occurred in 16 (34%) patients, anemia being the most common (n = 5); skin toxicity (n = 3); colitis (n = 2); adrenal insufficiency, acute kidney injury, allergic reaction, lipase, and amylase increased (n = 1 each). Conclusions: Bintrafusp alfa did not reach the expected efficacy in patients with advanced malignant pleural mesothelioma previously treated with platinum-based chemotherapy. Clinical trial information: NCT05005429 .

#565 Renal involvement in solid cancers: epidemiological, clinical and histological characteristics study of 154 onconephrology patients

Abstract Background and Aims Onconephrology is a growing discipline that aims to improve the management of patients with cancer and kidney disease. If renal histology is an essential key, the anatomopathological data remain weak. We propose an analysis of real-life data from patients managed in onconephrology consultations and had renal biopsy. Method Patients with active cancer who had a renal biopsy (RB) between 2015 and 2020 were included, and their clinicobiological and histological data were retrospectively analyzed. Our cohort consisted of 154 patients (83 women) with a mean age of 58 years who went for onconephrology care. Results One hundred twelve patients presented with proteinuria, 95 with acute renal failure, and 59 with arterial hypertension. Histologically, interstitial fibrosis was found in 74% of RBs, tubular atrophy in 55.1%, arteriolar hyalinosis in 58.4%, and fibrous endarteritis in 54.4%. Regarding the main acute lesions, thrombotic microangiopathy (TMA) was found in 29.9% of biopsies, acute tubular necrosis (ATN) in 51.3%, and acute interstitial nephritis in 24.8%. The etiological diagnosis most often made was the nephrotoxicity of anticancer drugs (87 patients), followed by a functional cause (15 patients) and renal disease unrelated to cancer (13 patients). Sixty-seven patients presented with at least 2 associated diagnoses. Different clusters were found, highlighting that anti-PD1 and anti-VEGF therapy were the most commonly involved drugs. Conclusion The nephrotoxicity of anticancer drugs was the etiology most often determined following RB this a onconephrology population, predominantly with diagnoses of TMA and ATN. Chronic histological lesions were very common. The etiological diagnoses were sometimes mixed, and primary or paraneoplastic glomerulopathies were detected mainly through histology.

Peptostreptococcus anaerobius mediates anti-PD1 therapy resistance and exacerbates colorectal cancer via myeloid-derived suppressor cells in mice

Bacteria such as the oral microbiome member Peptostreptococcus anaerobius can exacerbate colorectal cancer (CRC) development. Little is known regarding whether these immunomodulatory bacteria also affect antitumour immune checkpoint blockade therapy. Here we show that administration of P. anaerobius abolished the efficacy of anti-PD1 therapy in mouse models of CRC. P. anaerobius both induced intratumoral myeloid-derived suppressor cells (MDSCs) and stimulated their immunosuppressive activities to impair effective T cell responses. Mechanistically, P. anaerobius administration activated integrin α2β1–NF-κB signalling in CRC cells to induce secretion of CXCL1 and recruit CXCR2+ MDSCs into tumours. The bacterium also directly activated immunosuppressive activity of intratumoral MDSCs by secreting lytC_22, a protein that bound to the Slamf4 receptor on MDSCs and promoted ARG1 and iNOS expression. Finally, therapeutic targeting of either integrin α2β1 or the Slamf4 receptor were revealed as promising strategies to overcome P. anaerobius-mediated resistance to anti-PD1 therapy in CRC.

Open-label, phase II study of talimogene laherparepvec plus pembrolizumab for the treatment of advanced melanoma that progressed on prior anti–PD-1 therapy: MASTERKEY-115,

BackgroundTreatment options for immunotherapy-refractory melanoma are an unmet need. The MASTERKEY-115 phase II, open-label, multicenter trial evaluated talimogene laherparepvec (T-VEC) plus pembrolizumab in advanced melanoma that progressed on prior programmed cell death protein-1 (PD-1) inhibitors. MethodsCohorts 1 and 2 comprised patients (unresectable/metastatic melanoma) who had primary or acquired resistance, respectively, and disease progression within 12 weeks of their last anti–PD-1 dose. Cohorts 3 and 4 comprised patients (resectable disease) who underwent complete surgery, received adjuvant anti–PD-1, and experienced recurrence. Cohort 3 were disease-free for < 6 months and cohort 4 for ≥ 6 months after starting the adjuvant anti–PD-1 therapy and before confirmed recurrence. The primary endpoint was objective response rate (ORR) per RECIST v1.1. Secondary endpoints included complete response rate (CRR), disease control rate (DCR) and progression-free survival (PFS) per RECIST v1.1 and irRC-RECIST, and safety. ResultsOf the 72 enrolled patients, 71 were treated. The ORR (95% CI) was 0%, 6.7% (0.2–32.0), 40.0% (16.3–67.7), and 46.7% (21.3–73.4) in cohorts 1–4, respectively; iORR was 3.8% (0.1–19.6), 6.7% (0.2–32.0), 53.3% (26.6–78.7), and 46.7% (21.3–73.4). iCRR was 0%, 0%, 13.3%, and 13.3%. Median iPFS (months) was 5.5, 8.2, not estimable [NE], and NE for cohorts 1–4, respectively; iDCR was 50.0%, 40.0%, 73.3%, and 86.7%. Treatment-related adverse events (TRAEs), grade ≥ 3 TRAEs, serious AEs, and fatal AEs occurred in 54 (76.1%), 9 (12.7%), 24 (33.8%), and 10 (14.1%) patients, respectively. ConclusionT-VEC-pembrolizumab demonstrated antitumor activity and tolerability in PD-1−refractory melanoma, specifically in patients with disease recurrence on or after adjuvant anti–PD-1. Trial registrationClinicalTrials.gov identifier - NCT04068181

Plasma proteome profiling reveals dynamic of cholesterol marker after dual blocker therapy

Dual blocker therapy (DBT) has the enhanced antitumor benefits than the monotherapy. Yet, few effective biomarkers are developed to monitor the therapy response. Herein, we investigate the DBT longitudinal plasma proteome profiling including 113 longitudinal samples from 22 patients who received anti-PD1 and anti-CTLA4 DBT therapy. The results show the immune response and cholesterol metabolism are upregulated after the first DBT cycle. Notably, the cholesterol metabolism is activated in the disease non-progressive group (DNP) during the therapy. Correspondingly, the clinical indicator prealbumin (PA), free triiodothyronine (FT3) and triiodothyronine (T3) show significantly positive association with the cholesterol metabolism. Furthermore, by integrating proteome and radiology approach, we observe the high-density lipoprotein partial remodeling are activated in DNP group and identify a candidate biomarker APOC3 that can reflect DBT response. Above, we establish a machine learning model to predict the DBT response and the model performance is validated by an independent cohort with balanced accuracy is 0.96. Thus, the plasma proteome profiling strategy evaluates the alteration of cholesterol metabolism and identifies a panel of biomarkers in DBT.

HIV immunological non-responders are characterized by extensive immunosenescence and impaired lymphocyte cytokine production capacity.

Immunological non-responders (INR) are people living with HIV (PLHIV) who fail to fully restore CD4+ T-cell counts despite complete viral suppression with antiretroviral therapy (ART). INR are at higher risk for non-HIV related morbidity and mortality. Previous research suggest persistent qualitative defects. The 2000HIV study (clinical trials NTC03994835) enrolled 1895 PLHIV, divided in a discovery and validation cohort. PLHIV with CD4 T-cell count <350 cells/mm3 after ≥2 years of suppressive ART were defined as INR and were compared to immunological responders (IR) with CD4 T-cell count >500 cells/mm3. Logistic and rank based regression were used to analyze clinical data, extensive innate and adaptive immunophenotyping, and ex vivo monocyte and lymphocyte cytokine production after stimulation with various stimuli. The discovery cohort consisted of 62 INR and 1224 IR, the validation cohort of 26 INR and 243 IR. INR were older, had more advanced HIV disease before starting ART and had more frequently a history of non-AIDS related malignancy. INR had lower absolute CD4+ T-cell numbers in all subsets. Activated (HLA-DR+, CD38+) and exhausted (PD1+) subpopulations were proportionally increased in CD4 T-cells. Monocyte and granulocyte immunophenotypes were comparable. INR lymphocytes produced less IL-22, IFN-γ, IL-10 and IL-17 to stimuli. In contrast, monocyte cytokine production did not differ. The proportions of CD4+CD38+HLA-DR+ and CD4+PD1+ subpopulations showed an inversed correlation to lymphocyte cytokine production. INR compared to IR have hyperactivated and exhausted CD4+ T-cells in combination with lymphocyte functional impairment, while innate immune responses were comparable. Our data provide a rationale to consider the use of anti-PD1 therapy in INR.

Abstract PO2-03-05: Neoadjuvant anthracycline followed by Toripalimab combined with nab-paclitaxel in patients with stage IIA-IIIC triple negative breast cancer (NeoTENNIS): efficacy and safety results of a phase II study

Abstract Background: Immune checkpoint inhibitors(ICIs)have shown promising antitumor activity in triple negative breast cancer (TNBC) patients. Toripalimab, a novel PD-1 antibody, has been approved for the treatment in multiple solid tumors. However, the neoadjuvant use of toripalimab with chemotherapy has not been evaluated in TNBC patients. In addition, whether chemotherapy could sensitize the ICI treatment has not drawn conclusion yet. In this phase II trial, a sequential use of chemotherapy and anti-PD1 therapy was given in a neoadjuvant setting. The efficacy and safety of toripalimab were evaluated. Patients and methods: Female patients with histologically confirmed stage IIA to IIIC TNBC were included. Eligible patients received neoadjuvant therapy with four cycles of epirubicin-cyclophosphamide every 2 weeks followed by toripalimab (240 mg) every 3 weeks plus nab-paclitaxel weekly for 12 weeks. The primary endpoint was pathologic complete response (tpCR; ypT0/is ypN0) rate. Key secondary endpoints were breast pCR (bpCR; ypT0/is) rate, biomarker analysis, and safety. Results: Among 70 enrolled patients (median age, 51 years; 62.9% stage III), 66 patients completed study treatment without progression and received surgery after study treatment. Overall, the percentages of patients with a tpCR and bpCR were 55.7% (39 of 70 patients) and 58.6 % (41 of 70 patients), respectively. For women with CD8–positive and negative tumors, the tpCR rates were 66.0% and 30.0% (P = 0.006), respectively. Significant upregulation of CD8 positive cells after 4 cycles of epirubicin-cyclophosphamide induction chemotherapy (P = 0.011) were shown in sequential biopsy samples. Grade 3 or 4 treatment-related adverse events (TRAEs) occurred in 30 patients (42.9%), the most common of which were neutropenia (15.7%), leukopenia (14.3%) and alanine aminotransferase increase (4.3%). Most common immune-related AEs were hepatobiliary disorders (Grade 3, 7.2%), creatinine increase (all Grade 1-2, 2.8%) and hypothyroidism (all Grade 1-2, 2.8%). Conclusions: The addition of toripalimab to neoadjuvant chemotherapy is efficacious and safe in patients with locally advanced TNBC. Anthracycline-based chemotherapy could sensitize the ICI treatment with upregulated tumor immune response. The event-free survival results are expected with further follow up. Mechanisms of chemotherapy sensitization are still under investigation (ClinicalTrials.gov number: NCT04418154). Citation Format: Min He, Linxiaoxi Ma, Shuang Hao, Benlong Yang, Bingqiu Xiu, Ya-Yun Chi, Ruo-Hong Shui, Zhong-Hua Wang, Zhi-Ming Shao, Jiong Wu. Neoadjuvant anthracycline followed by Toripalimab combined with nab-paclitaxel in patients with stage IIA-IIIC triple negative breast cancer (NeoTENNIS): efficacy and safety results of a phase II study [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-03-05.

Formyl peptide enhances cancer immunotherapy by activating antitumoral neutrophils, and T cells

Neutrophils are heterogeneous and plastic, with the ability to polarize from antitumour to protumour phenotype and modulate tumour microenvironment components. While some advances have been made, the neutrophil-targeting therapy remains underexplored. Activation of formyl peptide receptors (FPRs) by formylated peptides is needed for local control of infection through the recruitment of activated neutrophils while the potential contribution of antitumour activity remains underexplored. Here, we demonstrate that neutrophils can be harnessed to suppress tumour growth through the action of the formyl peptide (FP) on the formyl peptide receptor (FPR). Mechanistically, FP efficiently recruits neutrophils to produce reactive oxygen species production (ROS), resulting in the direct killing of tumours. Antitumour functions disappeared when neutrophils were depleted by anti-Ly6G antibodies. Interestingly, extensive T-cell activation was observed in mouse tumours treated with FP, showing the potential to alter the immune suppressed tumour microenvironment (TME) and further sensitize mice to anti-PD1 therapy. Transcriptomic and flow cytometry analyses revealed the mechanisms of FP-sensitized anti-PD1 therapy, mainly including stimulated neutrophils and an altered immune-suppressed tumour microenvironment. Collectively, these data establish FP as an effective combination partner for sensitizing anti-PD1 therapy by stimulating tumour-infiltrated neutrophils.

Arsenic trioxide augments immunogenic cell death and induces cGAS-STING-IFN pathway activation in hepatocellular carcinoma

The treatment of hepatocellular carcinoma (HCC) is particularly challenging due to the inherent tumoral heterogeneity and easy resistance towards chemotherapy and immunotherapy. Arsenic trioxide (ATO) has emerged as a cytotoxic agent effective for treating solid tumors, including advanced HCC. However, its effectiveness in HCC treatment remains limited, and the underlying mechanisms are still uncertain. Therefore, this study aimed to characterize the effects and mechanisms of ATO in HCC. By evaluating the susceptibilities of human and murine HCC cell lines to ATO treatment, we discovered that HCC cells exhibited a range of sensitivity to ATO treatment, highlighting their inherent heterogeneity. A gene signature comprising 265 genes was identified to distinguish ATO-sensitive from ATO-insensitive cells. According to this signature, HCC patients have also been classified and exhibited differential features of ATO response. Our results showed that ATO treatment induced reactive oxygen species (ROS) accumulation and the activation of multiple cell death modalities, including necroptosis and ferroptosis, in ATO-sensitive HCC cells. Meanwhile, elevated tumoral immunogenicity was also observed in ATO-sensitive HCC cells. Similar effects were not observed in ATO-insensitive cells. We reported that ATO treatment induced mitochondrial injury and mtDNA release into the cytoplasm in ATO-sensitive HCC tumors. This subsequently activated the cGAS-STING-IFN axis, facilitating CD8+ T cell infiltration and activation. However, we found that the IFN pathway also induced tumoral PD-L1 expression, potentially antagonizing ATO-mediated immune attack. Additional anti-PD1 therapy promoted the anti-tumor response of ATO in ATO-sensitive HCC tumors. In summary, our data indicate that heterogeneous ATO responses exist in HCC tumors, and ATO treatment significantly induces immunogenic cell death (ICD) and activates the tumor-derived mtDNA-STING-IFN axis. These findings may offer a new perspective on the clinical treatment of HCC and warrant further study.

Anlotinib may enhance the efficacy of anti-PD1 therapy by inhibiting the AKT pathway and promoting the apoptosis of CAFs in lung adenocarcinoma

Although PD-1 inhibitors have revolutionized the treatment paradigm of non-small cell lung cancer (NSCLC), their efficacy in treating NSCLC has remained unsatisfactory. Targeting cancer-associated fibroblasts (CAFs) is a potential approach for improving the immunotherapy response. Multitarget antiangiogenic tyrosine kinase receptor inhibitors (TKIs) can enhance the efficacy of PD-1 inhibitors in NSCLC patients. However, the effects and mechanisms of antiangiogenic TKIs on CAFs have not been elucidated. In this study, we first compared anlotinib with other antiangiogenic TKIs and confirmed the superior efficacy of anlotinib. Furthermore, we established NSCLC-associated CAF models and found that anlotinib impaired CAF viability and migration capacity and contributed to CAF apoptosis and cell cycle arrest in the G2/M phase. Moreover, anlotinib treatment attenuated the capacity of CAFs to recruit lung cancer cells and macrophages. Experiments in animal models suggested that anlotinib could enhance the efficacy of anti-PD1 therapy in NSCLC and affect CAF proliferation and apoptosis. Anlotinib increased the abundance of tumor-infiltrating CD8 + T cells, and PD-1 inhibitor-induced cytotoxicity to tumor cells was achieved through the transformation of the tumor microenvironment (TME) caused by anlotinib, which may partly explain the synergistic antitumor effect of anlotinib and PD-1 inhibitors. Mechanistically, anlotinib affects CAF apoptosis and cell viability at least in part by inhibiting the AKT pathway. In conclusion, our study suggested that anlotinib could regulate the TME, inhibit the AKT pathway and promote CAF apoptosis, providing new insights into the antitumor effect of anlotinib and improving the efficacy of immunotherapy.

Patient-derived tumor-like cell clusters for personalized chemo- and immunotherapies in non-small cell lung cancer

Many patient-derived tumor models have emerged recently. However, their potential to guide personalized drug selection remains unclear. Here, we report patient-derived tumor-like cell clusters (PTCs) for non-small cell lung cancer (NSCLC), capable of conducting 100-5,000 drug tests within 10days. We have established 283 PTC models with an 81% success rate. PTCs contain primary tumor epithelium self-assembled with endogenous stromal and immune cells and show a high degree of similarity to the original tumors in phenotypic and genotypic features. Utilizing standardized culture and drug-response assessment protocols, PTC drug-testing assays reveal 89% overall consistency in prospectively predicting clinical outcomes, with 98.1% accuracy distinguishing complete/partial response from progressive disease. Notably, PTCs enable accurate prediction of clinical outcomes for patients undergoing anti-PD1 therapy by combining cell viability and IFN-γ value assessments. These findings suggest that PTCs could serve as a valuable preclinical model for personalized medicine and basic research in NSCLC.

Abstract LB076: Targeting an aging-related molecule overcomes resistance to anti-PD1 treatment of cancer

Abstract Purpose: Despite receiving great attention as a promising treatment, therapeutic efficacies induced by immune checkpoint inhibitors are low in clinical settings, and thus there are high expectations for the development of innovative diagnostic and therapeutic methods. We previously demonstrated that blocking FSTL1 overcomes anti-PD1 resistance in aged mice. In this study, we comprehensively analyzed and compared gene expressions in splenic T cells harvested from young and old mice receiving anti-FSTL1 or anti-PD1 therapy after tumor implantation using the GeneChip microarray in order to identify a key gene in the anti-PD1 resistance. In addition, we evaluated anti-tumor efficacy induced by blocking the identified molecule using aged tumor models and tumor metastasis models (3LL or Colon26), which are resistant to anti-PD1 therapy. Furthermore, to validate the clinical relevancy, we analyzed immune cells isolated from malignant tumor ascites and peripheral blood cells of gastric cancer patients by flow cytometry. Results: Using the GeneChip microarray data of splenic T cells, we identified α-synuclein (SNCA), which is a neuropathological molecule involved in Parkinson's disease and other synucleinopathies, as a gene that was significantly reduced by anti-FSTL1 therapy, but not anti-PD1 therapy, in splenic T cells of aged tumor models. SNCA+ cell subsets significantly increased not only in CD3+ T cells, but also CD11b+ myeloid cells and CD45- mesenchymal stromal/stem cells, within spleen, peripheral blood, and tumor tissues of aged mice and mouse tumor models, but rarely in those of young and naive mice. Increase of the subsets were also observed in malignant tumor ascites and peripheral blood of gastric cancer patients, but not those of healthy donors. Blocking SNCA with the specific mAb significantly induced potent CD8+ T cells with greater cytotoxicity in the in vitro CTL induction setting, and also significantly induced robust anti-tumor immunity in the in vivo therapeutic setting with anti-PD1-resistant tumor models. Combination of anti-SNCA therapy successfully elicited anti-PD1 therapeutic efficacy, providing significantly better prognosis in many tumor models, including severe tumor ascites models. Conclusions: These results suggest that SNCA is a type of immune inhibitory checkpoint molecules and an immunological determinant of anti-PD1 resistance, although the further study is needed to clarify the molecular functions in immune cells. Targeting this molecule may represent a promising strategy to overcome the anti-PD1 resistance and contribute to improved clinical outcomes in cancer treatment. Citation Format: Chie Kudo-Saito, Hiroshi Imazeki, Hirokazu Shoji, Narikazu Boku. Targeting an aging-related molecule overcomes resistance to anti-PD1 treatment of cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB076.

Early Serum Markers for Immune Checkpoint Inhibitor Induced Hypophysitis in Melanoma Patients.

Immune checkpoint inhibitors (ICIs) have shown promising anti-tumor activities and are widely used for the treatment of advanced cancers. However, they may lead to immune-related adverse events (irAEs) and some of them, such as hypophysitis, can be life-threatening. Here, early diagnosis is critical. We retrospectively analyzed 40 melanoma patients who developed hypophysitis during ICI treatment with either ipilimumab and/or anti-PD1 therapy and compared them to 40 control patients who did not develop hypophysitis during the ICI treatment, matched for age, gender, type of immunotherapy, and stage. Clinical data and blood values such as LDH, CRP, TSH, T3, T4, and absolute immune cell counts were retrieved from the medical records. Patient characteristics, laboratory values, progression-free survival, and overall survival were compared between the two groups. Patients with ir-hypophysitis had a median age of 59 years, and most of them were male. Clinically, frequent symptoms were fatigue, headache, dizziness, and gastrointestinal symptoms such as nausea or abdominal pain. The onset of ir-hypophysitis differed much between ipilimumab- (median 8 weeks) and anti-PD1 (median 40 weeks)-induced hypophysitis (p < 0.001). At baseline, besides a slightly increased CRP level (p = 0.06), no differences were observed in patients who later developed hypophysitis compared to the control. After treatment started, hypophysitis patients showed a constant and significant decline in T4 levels from the start of therapy until diagnosis (p < 0.05), independent of the ICI treatment regime. However, a decline in T3 and TSH was only noted in patients with ipilimumab-induced ir-hypophysitis. Furthermore, serum sodium levels declined rapidly at the diagnosis of hypophysitis (p < 0.001). In addition, there was a constant increase in the absolute counts of eosinophils and lymphocytes from baseline in hypophysitis patients (p < 0.05). Ir-hypophysitis reveals different clinical pictures and onset times depending on the ICI regime used. Whereas a drop in T4 levels was indicative of developing hypophysitis independent of the ICI regime, TSH levels only declined in patients under ipilimumab-based ICI regimes. To best monitor our patients, it is important to recognize these differences.

Glutamine antagonist DRP-104 suppresses tumor growth and enhances response to checkpoint blockade in KEAP1 mutant lung cancer.

Loss-of-function mutations in KEAP1 frequently occur in lung cancer and are associated with poor prognosis and resistance to standard of care treatment, highlighting the need for the development of targeted therapies. We previously showed that KEAP1 mutant tumors consume glutamine to support the metabolic rewiring associated with NRF2-dependent antioxidant production. Here, using preclinical patient-derived xenograft models and antigenic orthotopic lung cancer models, we show that the glutamine antagonist prodrug DRP-104 impairs the growth of KEAP1 mutant tumors. We find that DRP-104 suppresses KEAP1 mutant tumors by inhibiting glutamine-dependent nucleotide synthesis and promoting antitumor T cell responses. Using multimodal single-cell sequencing and ex vivo functional assays, we demonstrate that DRP-104 reverses T cell exhaustion, decreases Tregs, and enhances the function of CD4 and CD8 T cells, culminating in an improved response to anti-PD1 therapy. Our preclinical findings provide compelling evidence that DRP-104, currently in clinical trials, offers a promising therapeutic approach for treating patients with KEAP1 mutant lung cancer.

Neoadjuvant Dual Checkpoint Inhibitors vs Anti-PD1 Therapy in High-Risk Resectable Melanoma

Despite the clear potential benefits of neoadjuvant therapy, the optimal neoadjuvant regimen for patients with high-risk resectable melanoma (HRRM) is not known. To compare the safety and efficacy of dual checkpoint inhibitors with anti-programmed cell death protein-1 (anti-PD1) therapy in a neoadjuvant setting among patients with HRRM. In this pooled analysis of clinical trials, studies were selected provided they investigated immune checkpoint inhibitor treatment, were published between January 2018 and March 2023, and were phase 1, 2, or 3 clinical trials. Participant data included in the analysis were derived from trials evaluating the efficacy and safety of anti-PD1 monotherapy and the combination of anti-cytotoxic T lymphocyte-associated protein-4 with anti-PD1 in the neoadjuvant setting, specifically among patients with HRRM. Patients were treated with either anti-PD1 monotherapy; dual checkpoint inhibition (DCPI) with a conventional dose of 3-mg/kg ipilimumab and 1-mg/kg nivolumab; or DCPI with an alternative-dose regimen of 1-mg/kg ipilimumab and 3-mg/kg nivolumab. The main outcomes were radiologic complete response (rCR), radiologic overall objective response (rOOR), and radiologic progressive disease. Also, pathologic complete response (pCR), the proportion of patients undergoing surgical resection, and occurrence of grade 3 or 4 immune-related adverse events (irAEs) were considered. Among 573 patients enrolled in 6 clinical trials, neoadjuvant therapy with DCPI was associated with higher odds of achieving pCR compared with anti-PD1 monotherapy (odds ratio [OR], 3.16; P < .001). DCPI was associated with higher odds of grade 3 or 4 irAEs compared with anti-PD1 monotherapy (OR, 3.75; P < .001). When comparing the alternative-dose ipilimumab and nivolumab (IPI-NIVO) regimen with conventional-dose IPI-NIVO, no statistically significant difference in rCR, rOOR, radiologic progressive disease, or pCR was noted. However, the conventional-dose IPI-NIVO regimen was associated with increased grade 3 or 4 irAEs (OR, 4.76; P < .001). Conventional-dose IPI-NIVO was associated with greater odds of achieving improved rOOR (OR, 1.95; P = .046) and pCR (OR, 2.99; P < .001) compared with anti-PD1 monotherapy. The alternative dose of IPI-NIVO also was associated with higher odds of achieving rCR (OR, 2.55; P = .03) and pCR (OR, 3.87; P < .001) compared with anti-PD1 monotherapy. The risk for grade 3 or 4 irAEs is higher with both the conventional-dose (OR, 9.59; P < .001) and alternative-dose IPI-NIVO regimens (OR, 2.02; P = .02) compared with anti-PD1 monotherapy. In this pooled analysis of 6 clinical trials, although DCPI was associated with increased likelihood of achieving pathological and radiologic responses, the associated risk for grade 3 or 4 irAEs was significantly lower with anti-PD1 monotherapy in the neoadjuvant setting for HRRM. Additionally, compared with alternative-dose IPI-NIVO, the conventional dose of IPI-NIVO was associated with increased risk for grade 3 or 4 irAEs, with no significant distinctions in radiologic or pathologic efficacy.

Assessing the use of anti-PD1 monotherapy as adjuvant therapy and determinants of treatment choice in stage III cutaneous melanoma in the US

BackgroundThe objective of this study was to describe real-world adjuvant therapy (AT) use by disease substage and assess determinants of treatment choice among patients with stage III melanoma.MethodsThis non-interventional retrospective study included survey responses and data from patient records provided by US medical oncologists. Survey responses, patient demographic/clinical characteristics, treatment utilization, and reasons for treatment were reported descriptively. The association between patient and disease characteristics and AT selection was assessed using logistic and multinomial regression models, overall and stratified by AJCC8 substage (IIIA vs. IIIB/C/D) and type of AT received (anti-PD1 monotherapy, BRAF/MEK, no AT), respectively.ResultsIn total 152 medical oncologists completed the survey and reviewed the charts of 507 patients (168 stage IIIA; 339 stages IIIB/IIIC/IIID); 405 (79.9%) patients received AT (360/405 (88.9%) received anti-PD1 therapy; 45/405 (11.1%) received BRAF/MEK therapy). Physicians reported clinical guidelines (61.2%), treatment efficacy (37.5%), and ECOG performance status (31.6%) as drivers of AT prescription. Patient-level data confirmed that improving patient outcomes (79%) was the main reason for anti-PD1 prescription; expected limited treatment benefit (37%), patient refusal (36%), and toxicity concerns (30%) were reasons for not prescribing AT. In multivariable analyses stage IIIB/IIIC/IIID disease significantly increased the probability of receiving AT (odds ratio [OR] 1.74) and anti-PD1 therapy (OR 1.82); ECOG 2/3 and Medicaid/no insurance decreased the probability of AT receipt (OR 0.37 and 0.42, respectively) and anti-PD1 therapy (OR 0.41 and 0.42, respectively) among all patients and patients with stage IIIA disease.ConclusionMost patients were given AT with a vast majority treated with an anti-PD1 therapy. Physician- and patient-level evidence confirmed the impact of disease substage on AT use, with stage IIIA patients, patients without adequate insurance coverage, and worse ECOG status having a lower probability of receiving AT.

Abstract 3963: Indoleamine 2,3-dioxygenase 1 (IDO1) regulates immune evasion in lymphoma

Abstract Recently, anti-programmed death (anti-PD) therapy has been at the forefront of cancer therapy. However, the clinical efficacy of anti-PD therapy in DLBCL remains obscure. The marginal response to anti-PD therapy in DLBCL indicates that different mechanisms of immune evasion other than the PD-1/PD-L1 pathway may be present. To investigate the mechanisms of resistance to anti-PD therapy in DLBCL, we assessed gene expression in patients with DLBCL in public database. Accordingly, we found indoleamine 2,3-dioxygenase 1 (IDO1), a key enzyme responsible for tryptophan catabolism, is highly expressed in DLBCL. IDO1 expression is upregulated by IFN-gamma produced by T cells in tumor microenvironments (TMEs) of various cancer types. Upregulated IDO1 leads to the production of kynurenine, which creates an immunosuppressive TMEs. However, it remains unknown whether IDO1 induces immune evasion in DLBCL and if so, which subsets of IDO1 expressing cells are responsible for immune evasion in DLBCL. To address these questions, we first determined the intrinsic role of IDO1 in lymphoma cells. We knocked down IDO1 expression (IDO1 KD) in a human DLBCL RC-K8 cell line using short hairpin RNA. We observed decreased cell proliferation in IDO KD lymphoma cells compared with control cells. We also found increased susceptibility to apoptosis in IDO1 KD RC-K8 cells compared with IDO1 WT control, when these were co-cultured with THP-1-derived macrophages or activated Jurkat T lymphocytes. These data suggest that lymphoma IDO1 has an intrinsic role of lymphoma progression and makes lymphoma sensitive to cytotoxic immune cells. To validate the anti-tumor effect of IDO1 deficiency in immune cells, we assessed EL4 lymphoma growth and immune TME of lymphoma in syngeneic wild type (WT) and Ido1 knock-out (KO) mice. The growth of EL4 lymphoma tumor was significantly suppressed in Ido1 KO mice compared to WT mice (Ido1 KO: 621.9mm3 vs WT: 1228mm3, N=22, P&amp;lt;0.001). Immune TME assessment revealed a decreased frequency of regulatory T cells, yet, the increased proportions of B cells, MHC II+ antigen-presenting cells, monocytes, and NK cells in Ido1 KO tumors compared with WT control. In summary, IDO1 is highly expressed in DLBCL. IDO1 up-regulation may drive lymphoma progression both intrinsically and extrinsically (immune evasion). This data suggests that IDO1 overexpression may be one of the mechanisms of resistance to anti-PD therapy. We will extend our studies to determine a combination effect of IDO1 inhibitors with immune checkpoint inhibitors including anti-PD therapy in DLBCL. Citation Format: Jihyun Park, Seung-Joo Yoo, Qianni Hu, Carly M. Fielder, Hyundong Yoon, Junshik Hong, Byung-Su Kim, Youngil Koh, Tae Kon Kim, Sung-Soo Yoon, Chi Yan. Indoleamine 2,3-dioxygenase 1 (IDO1) regulates immune evasion in lymphoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3963.

Abstract 1441: Establishing a novel clinically relevant disease model of glioblastoma

Abstract Introduction: GBM is the most common primary malignancy of the CNS. Historically pre-clinical models have failed to predict response in humans, despite promising preclinical data. Moreover, current models seldom incorporate surgical resection and/or standard of care chemotherapy treatment. These models also commonly employ young animals exclusively, whose immune contexture differs from older patients. We therefore sought to establish an improved, orthotopic, preclinical GBM model, which better recapitulates patient response to standard-of-care and targeted treatments. Methods: NFpp10a-Luc2 GBM cells were orthotopically implanted into C57BL/6-mice (aged[&amp;gt;18months] and young[6-8weeks]) and weekly bioluminescence imaging performed to monitor tumor growth. Overall survival (OS) and tumor growth were assessed in response to (1) Surgical Resection, (2) Temozolomide (TMZ) (3) anti-PD1 (4) neoadjuvant anti-PD1 and (5) Regorafenib (REGO) therapy. Tissue collected post-mortem underwent bulk RNA sequencing followed by analysis via microenvironment cell population counter (MCP) and gene set enrichment (GSEA) to determine changes in the GBM-TME following treatment. Results: We demonstrated OS advantage in aged mice undergoing surgical resection (Resection:33.5 days vs Non-Resection: 18 days; p=0.0166) and observed age to be a significant prognostic factor (Young:62 days vs Aged: 22 days; p=0.0002). Subsequently, we observed that TMZ and anti-PD1 monotherapies had no impact on NFpp10-Luc2 growth (p=0.9001, p=0.7933) or survival (p=0.3035, p=0.6328). Neoadjuvant anti-PD1 treated mice demonstrated no significant survival advantage compared to IgG control (33 days vs 35 days; p=0.9429). Lastly, REGO treatment demonstrated a trend towards improved OS vs Vehicle (p=0.096). MCP analysis revealed both neoadjuvant anti-PD1 and REGO treatment induced influx of CD8+ T cells, B cells and monocytes into the TME, with neoadjuvant anti-PD1 associated with an upregulation of CXCR3 (p=0.0045). Conclusions: We have, for the first time, established and characterized response of the NFpp10a-C57BL/6 model to surgical resection, TMZ, anti-PD1 and REGO therapy in both young and aged mice. We have shown the model is markedly insensitive to intervention with chemotherapy and immune checkpoint therapy, mirroring what is seen clinically in patients. The model may therefore be employed in future pre-clinical studies to guide clinical trials in the setting of mesenchymal GBM. Citation Format: Kate Connor, Kieron White, James Clerkin, Kieron Sweeney, Liam Shiels, Thomas van Brussel, Ingrid Arijs, Diether Lambrechts, Gautam Shankar, Frederik de Smet, Stephen G. Maher, Laure Marignol, Patrick Dicker, Jochen Prehn, David O'Brien, Annette T. Byrne. Establishing a novel clinically relevant disease model of glioblastoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1441.

Abstract 2703: Targeting STING pathway as a therapeutic strategy against β-catenin driven immune escape and resistance to anti-PD1 therapy in hepatocellular carcinoma

Abstract β-catenin mutation occurs in around 40% of hepatocellular carcinoma(HCC); yet no precision therapies are available to treat this tumor subset. Immune checkpoint inhibitors (ICIs) are now widely used for the treatment of patients with advanced HCC. Unfortunately, preliminary evidence showed that β-catenin mutation drives resistance to anti-PD1 immunotherapy in HCC. In this study, we studied the molecular mechanisms underlying β-catenin mutation during HCC pathogenesis to develop novel therapeutics targeting β-Catenin-driven HCC. Firstly, three HCC cohorts were examined, including 70 untreated, 20 treated patients with nivolumab, and patients from a public TCGA database. By single-cell RNA sequencing analysis, we identified that anti-PD-1 treatment displayed effectiveness with the increase of CD27+CD8+ T-cell infiltration, correlating to improved prognosis with longer progression-free survival (PFS) and OS. Importantly, multiplex IHC staining showed that β-catenin activation is associated with significantly reduced CD8+CD27+ T cell infiltration in tumors (n=70), demonstrating that β-catenin promoted immune escape and resistance to anti-PD-1 treatment involved defective cytotoxic T-cell activity. Subsequently, we found that the interaction of β-Catenin with sirtuin 1 (SIRT1) mediated suppression of IRF3/IRF7 activity, resulting in inhibition of Type I interferon (IFN-I) production. However, by CRISPRi screening, we found that disruption of β-catenin-SIRT1 interaction via STING caused persistent high-level IFN-I response which increased the transcription of T-cell costimulatory molecule CD27 via IL10/STAT3/BATF signaling on infiltrated CD8+ T cells. This effect was also confirmed in the STING null mice, emphasizing that STING signaling is a therapeutic target to overcome β-catenin driven immune escape. Further, using hydrodynamic tail-vein injection murine HCC models, we found that the STING agonist inhibited β-catenin-SIRT1 activity, restored IFN signaling to rescue T-cell cytotoxic capacities, and enhanced the anti-PD-1 therapy efficacy. In conclusion, we demonstrated that STING reprogrammed β-Catenin mutated the HCC tumor microenvironment and a combination of STING and anti-PD-1 treatment represents an effective novel therapeutic strategy for HCC patients with β-Catenin mutation. Citation Format: Qingmei Zhang, Jiacheng Bi, Oscar Wai-Ho Yeung, Tao Ding, Wing-Lim Chan, Yueqin Zhu, Jiang Liu, Kevin Tak-Pan Ng, Kwan Man. Targeting STING pathway as a therapeutic strategy against β-catenin driven immune escape and resistance to anti-PD1 therapy in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2703.

Abstract 5251: RNA primed SMAR-T cells against multiple driver mutations, all HLA's designed for first line therapy

Abstract Success of immune checkpoint inhibitors (e.g., anti-PD1 antibodies) have revolutionized cancer immunotherapy by demonstrating that a patient’s own T-cells recognize and treat cancer. The efficacy of PD-1 blockade is driven by recruitment of new T-cells from blood rather than via activation of pre-existing tumor infiltrating lymphocytes (Yost K.E., et al. Nat. Med. 2019). However, anti-PD1 therapy is most effective in ~5% of malignancies i.e., cancers with high mutational burden. Hence, the challenge of addressing most lower mutational burden cancers (the ~95%) needs an alternate treatment strategy. We address this challenge by using RNA to prime and expand peripheral T-cells to cancer-specific mutations ex-vivo. Using our proprietary, patented, and robust manufacturing method, we can generate T-cell populations reactive to as low as 8 and as high as 40 cancer-specific mutant proteins. In-vitro, these T-cells have cancer mutation-specific cytotoxicity and do not kill the normal cells. Further, the T-cells express homing receptors enabling them to infiltrate tumors and express high levels of TNFα and IFNγ, which are associated with effective tumor cytotoxicity and pro-inflammatory modification of tumor microenvironment (TME). Additional characterization shows these cells to be predominantly CD4+ and CD8+ T-cells bearing central and effector memory phenotypic with negligible regulatory or exhausted T-cells. We believe our T-cells can be used for cellular therapy in conjunction with, or as an alternative to, immune checkpoint inhibitors to treat lower mutational burden cancers present in most patients. Citation Format: Alfred E. Slanetz, Sriram Srivatsa, Farzona Muzaffar, Walter Barry, David Ryan, Salim Metri, Michael Slanetz. RNA primed SMAR-T cells against multiple driver mutations, all HLA's designed for first line therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5251.